The oviducts of various avian species are able to storespermatozoa for periods ranging up to several months. The sites of sperm storagein several domestic birds have been clearly defined as tubular glands (sperm storage glands)located at the junction of the uterus and vagina. The biochemical features of thes glands which are responsible for their sperm storing ability are unknown. The purpose of the present study is to gain an understanding of the biochemical nature of this region of the oviduct and relate it to the sperm storing ability. In particular, the possible role of the mineral ions K, Na and Ca in this function will be investigated. In addition, the possible role of glycerylphosphorylcholine(GPC) in sperm storage by the avian oviduct will be studied. The secretions of the shell gland (uterus) of the chicken and turkey show striking changes in K content during the formation of each egg. The role of K in maintaining sperm in the mammalian epididymis has been repeatedly suggested. In this study we will measure the K content of uterine and vaginal secretions and of sperm storage gland tissue. Measurements of Na and Ca will be made on the same materials. We will attempt to modify the mineral ion content of oviducal secretions with mineralocorticoid hormones and study the effect on the fertility of these birds. Determination of the effects of this hormone treatment on mineral ion composition will be measured by atomic absorption spectrophotometry. The mineral ion composition and mineralocorticoid levels of hens with histories of high, intermediate and low fertility will be determined. The high levels of glycerylphorylcholine in epididymal secretions and in uterovaginal tissue of the turkey may indicate a common role of this compound in maintaining the life of sperm in these two structures. Quantitative determination of GPC levels in sperm storage gland tissue and oviducal secretions, of hens of differing levels of fertility, will be made.